Water heater



H. A. MILLS WATER HEATER July 2, 1935.

Original Filed-April 19, 1930 2 Sheets-Sheet l INVENTOR. flax/ 1 fl MMA s.

BY WXWW A TTORNEY July 2, 1935. H. A. MILLS 2,006,838

WATER HEATER Original Filed April 19; 1950 2 Sheets-Sheet 2 QQQQQQ INVEN TOR. f/HKK V 5 MA. A s.

A TTORNEYJ.

Patented July 2, 1935 UNITED ,smrss WATER HEATER Harry A. Mills, Noblesville, Ind.

Refile for abandoned 445,597, April 19, 1930.

tober 18, 1934, Serial 3 Claims.

This invention relates to a method and apparatus for heating water, particularly for use with hard water containing a high percentage of encrusting chemicals.

The principal object of the invention is to provide a method and apparatus of heating water such that the'said chemicals are largely prevented from being deposited upon the heating surface and in which no softening means of a chemical nature is used. In heating water by the methods heretofore in common use, it has been the practice to bring the Water to be heated into contact with one side of a heat transfer surface, the opposite side of which is heated by a flame at high temperature. The water is thus brought to a high enough temperature to deposit encrusting solids although the final desired temperature of the water may be considerably lower. The said solids reduce the efliciency of the heat transfer surface and, in the case of such surfaces formed of pipes or tubes, this often results in clogging and burning out of the tubes.

The principal feature of the invention resides in the provision of a means of circulating a quantity of water about a closed path. The said water is heated in a heater coil at one point in said path and at another point is passed through a secondary heat-exchanging element in contact with a second body of water to be heated. The heat, therefore, is transferred from the circulated Water to the water to be heated in the said secondary heat-exchanging element. The circulated water at the point where it is heated is brought to a temperature sufficient to deposit the encrusting solids therein, but since the same water is repeatedly reheated, the deposition of said solids is not repeated. At the 40 point of transfer of heat from the circulated water to the second body of water, the second body of water is ordinarily not brought to a temperature for deposition of chemicals. The secondary heat transfer element, therefore, is also maintained at its greatest efficiency.

A connection is provided between the circulating water path and the water to be heated for maintaining a sufficient quantity of circulating water and for preventing excess pressure 50 in the circulating water path in case the said Water is heated above its boiling point. The said connection is arranged, however, so that the tendency of water to flow therethrough is reduced to the minimum. The circulating Water, therefore, after being once heated, is not greatly application Serial No.

This application Oc- No. 748,941

hardened by the addition of hard water through the said connection.

Other features of the invention reside in the specific form of apparatus herein disclosed although other apparatus may be used for carrying out the method of the invention.

Other objects and features of the invention will be understood from the accompanying drawings and the following description an claims:

Fig. 1 illustrates a heater embodying the invention herein shown connected to a storage reservoir for hot water. Fig. 2 is a vertical central section through said heater taken on the line 22 of Figs. 3 and 4. Figs. 3 and 4 are horizontal sectional views of the said heater taken on the line 33 and 45 respectively of Fig. 2. Fig. 5 is a vertical central section through an alternative form of heater embodying the invention. Fig. 6 is a horizontal sectional view taken on line 65 of Fig. 5.

In Fig. l the heater is indicated generally by the numeral l9 and is connected to a hot water storage reservoir 5! by means of pipes 52 and IS. The heater I comprises a casing M having a partition l5 therein dividing. the same into a water space it and a combustion space H. A hinged door l8 permits access to said combustion space. A burner I P: is located at the bottom of the combustion space i! and may be of any suitable design adapted to burn any suitable fuel. A heating coil 20 located at the combustion space H and a second coil 2| is located in the water space 16. The lower ends of said coils are connected together by means of a pipe connection 22. The upper ends of said coils are connected together by means of a pipe connection 23. The coils 2i] and 2i and connections 22 and 23 constitute a circulating path for Water heated by the flame from burner 19. The water space It is provided with a cover 24 and is connected to pipes l2 and [3 leading to the reservoir II. A pipe 25 connects the pipe 13 with the pipe connection 23 and serves to 4 maintain a proper quantity of circulating Water and to prevent excess pressure in the coils 20 and 2|. The pipe 25 includes an expansion coil 26.

In the operation of the apparatus, the circulating water is heated in coil 20 to a temperature suflicient to deposit the encrusting solids. The convection current caused by the heating circulates the Water through coils 20 and 21. In

I space.

thewater in both the pipe connection 23 and pipe I3 is at a relatively high temperature,.

there is small tendency for a two-way convection current to be established in pipe 25, thus .the softness of the circulating water is not greatly affected by addition of water. The use of the expansion coil 26 takes care of expansion of the heated cirulating water and prevents drawing in of any great quantity of hard water when the said circulating water is cooled. The form of heater herein illustrated is particularly applicable to household use. In such use it is often desirable in winter time to heat the water by means of a coil placed within the furnace used to heat the house. The said furnace coil may be connected directly to connections 22 and 23 and, therefore, functions in exactly the same manner as the coil 20.

When it is desired to heat the "water in space I6 above the temperature of deposition of chemicals, the same apparatus is applicable and presents advantages over apparatus heretofore in I use. In that case, such solids are deposited upon the outside of the tubes of coil 2I fromwhich they may be easily removed. Such solids as do not adhereto the tubes drop to the bottom of chamber I6 where no harm can be done thereby. a I

In Figs. and 6 there is illustrated an alternative form of heater embodying the invention in which a cylindrical casing H4 is divided by means of a partition H5 into a water space H6 and a heating space or combustion space III. A burner H9 is located at the lower end of the combustion space H1 and serves to heat water in a coil I20 contained in' the said combustion A coil I 2I is contained in the water space I I6 and connects at its lower end with the lower end of the coil I20 by means of a pipe I22. The upper ends of coils I20 and I2I are connected by means of a pipel23. The water space H6 is fitted with a cold water intake pipe H2 and av hot water outlet pipe H3 which may be connected to ahot water reservoir similar to that illustrated in Fig. 1. A pipe I25 connects the pipe II3 with the pipe I23 and serves a purpose analogous to pipe 25 in the previously described apparatus. The pipe I25 is looped about the heater as shown in Fig. 5'forthe purpose of adding suflicient length thereto to provide for expansion of water heated in the circulating system. A pair of pipes I21 and I28 lead from the lower and upper ends of the coils I2I and I22 and may be connected to heatingcoils located within a house heating furnace as previously mentioned. 7

In the operation of this form of apparatus, circulating water is heated in the primary heatexchanging element, coil I20, and circulates through the saidcoil and through coil I2I. The water in coil I2I gives up its heat to the water in the water space I I6 without ordinarily raising the said water to a temperature at which solids will be deposited. In addition, the partition H5 serves as a heat transfer surface but since the flame from burner H9 is largely confined within the interior of coil I20 this transfer of heat ordinarily does not serve to bring thewater in the space H6 above the desired temperature.

The invention claimed is:

1. Apparatus for heating hard water including a casing, a partition in said casing dividing the same into a closed water chamber and a heater space, an inlet pipe for introducing water to be heated into said water chamber, an outlet pipe for removing heated water therefrom, a coil in said water chamber, a heater coil'in said heater space, means for heating water in said heater coil, connections between said coils for permitting circulation of heated water therethrough for heating the water in saidwater chamber, a connection between said. coilsv and said outlet pipe for maintaining equal pressure upon the water in said coils and said water chamber, and an expansion coil associated with said lastmentioned connection. i

2. Apparatus for heating waterincludinga casing, a second casing surroundingthe same and forming a water space between said casings, a primary heating coil within said first-mentioned casing, a secondary heating coil within said water space, means for heating water in said primary coil, connections between said coils for permitting circulation of water therethrough, an outlet pipe from said water space, and a pipe connection between said outlet pipe and said coils, said pipe connection being looped about said heater to provide suflicient length for accommodation of expansion of heated water.

3. Apparatus for heating hard water including 

